02 dicembre 2014
What and Why
A quick background:
- Among young adults (15-29), suicide accounts for 8.5% of all deaths: second leading cause of death (after traffic accidents).
- Among adults (30-49) suicide accounts for 4.1% of all deaths: fifth leading cause of death.
(see the latest "Prevent Suicide" report by WHO)
"The debate about the impact of climate change on human health has, very recently, included consideration of mental health" (Berry, Bowen & Kjellstrom, 2009).
The mental health vs climate relationship still needs to be studied into details (research gap).
Research question:
How do climate factors affect suicide rate in the Italian context?
- Is suicide rate lower whereby the average temperature is higher?
- Is suicide rate higher whereby the average temperature range is higher?
- Is suicide rate higher whereby precipitations happen more frequently?
Methodology
Case selection:
Previous study: regional data, 20 observations, unsignificant model.
Now, Italy is still our focus: county-level data provide 110 observations!
Our Models:
\[ LogStSuicideRate = \alpha + \beta_{1}LogGDPPerCapita + \beta_{2}LogUnemploymentRate \] \[ + \beta_{3}LogPopulation + \beta_{4}LogGiniIndex + \beta_{5}LogAverageTemperature \] \[ + \beta_{6}LogAverageTemperatureRange + \beta_{7}LogAveragePrecipitations + e \]
\[ LogSuicideRate = \alpha + \beta_{1} + \beta_{2}LogUnemploymentRate \] \[ + \beta_{3}LogPopulation + \beta_{4}LogAverageTemperature \] \[ + \beta_{5}LogAveragePrecipitations + e \]
Findings
| Dependent variable: | ||
| St. suicide rate | ||
| (1) | (2) | |
| GDP per capita | 0.699*** | 0.529*** |
| (0.211) | (0.117) | |
| Unemployment rate | 0.086 | |
| (0.106) | ||
| Population | -0.174*** | -0.158*** |
| (0.043) | (0.039) | |
| Gini index | 0.173 | |
| (0.487) | ||
| Average Temperature | -0.072 | -0.069 |
| (0.097) | (0.092) | |
| Temperature range | -0.066 | |
| (0.211) | ||
| Average Precipitations | -0.435*** | -0.461*** |
| (0.147) | (0.143) | |
| Constant | 5.312*** | 5.622*** |
| (1.415) | (1.123) | |
| Observations | 103 | 103 |
| R2 | 0.372 | 0.365 |
| Adjusted R2 | 0.326 | 0.339 |
| Residual Std. Error | 0.264 (df = 95) | 0.261 (df = 98) |
| F Statistic | 8.041*** (df = 7; 95) | 14.086*** (df = 4; 98) |
| Note: | p<0.1; p<0.05; p<0.01 | |
| Model1 | Model2 |
Predicted Probabilities
How to cite this model in Zelig: Kosuke Imai, Gary King, and Olivia Lau. 2014. "ls: Least Squares Regression for Continuous Dependent Variables" in Kosuke Imai, Gary King, and Olivia Lau, "Zelig: Everyone's Statistical Software," http://gking.harvard.edu/zelig
